High tension electrical switch



Sept. 15, 1942. T. F. JOHNSON HIGH TENSONv ELECTRICAL SWITCH Filed March 26, 1940 2 Sheets-Sheet l w/bomm sept. 15, 1942. T F, JOHNSQN 2,295,663

'iIGH TENSION ELECTRICAL SWITCH Filed March 26, 1940 2 Sheets-Sheet 2 Patented Sept. 15, 1942 UNITED STATES PATENT OFFICE 2' Claims.

This invention relates to high tension electrical switches and, among other objects, aims to provide a greatly improved arc extinguishing attachment for increasing the interrupting capacity of load-breaking, stick-operated, disconv necting switches. The main idea is to provide an attachment which is automatically operated upon manual actuation of a switch of this type to prevent an arc from being formed between the tip of the switch blade and its contact and to cause the arc to be extinguished within an insulated tube so that the contact and blade tip will not be burned.

Other aims and advantages of the invention will appear in the specification, when considered iny connection with the accompanying drawings, .Whereinz Fig. l is a side elevation of a switch embodying the invention;

Fig. 2 is a sectional view taken on the line 2 2 of Fig. l;

Fig. 3 is a fragmentary sectional view taken on the line 3 3 of Fig. l;

Fig. 4 is a longitudinal vertical sectional view, partly in elevation, of the switch shown in Fig. l; and

Fig. 5 is a bottom plan view.

Referring particularly to the drawings, the type of switch there shown is designed to be employed in connection with high tension equipment when it is impracticable to employ gangoperated switches, due to lack of available space for multiple actuation. Such switches heretofore have not been adapted to be opened under load because of the destructive arcing effect. In this example, a single-phase switch is shown as being mounted in inverted position so that the switch blade opens downwardly. However, it is to be understood that such switches may be mounted vertically with the blade tips at the top to swing outwardly and downwardly. In this instance, the switch is supported by a channel I3 or other suitable member having depending spaced insulators I| and I2. The insulator II carries a cast metal hinge bracket I3 having a line terminal I4 and a switch blade I5 having bifurcated hinge arms I6 and is conveniently made of two pieces of strap metal, such as copper.

The insulator I2 carries a metal bracket I'I with a line terminal I 8 and a pair of spring locking jaws I9 adapted to prevent the blade from dropping out accidentally. The tip is shown as having a combination operating member and prying lever member 2|) with double hooks 2| to be engaged by an ordinary switch hook and it has a r switch arm 2v2 adapted to pry open the jaws I9 to release the blade tip therefrom, thus permitting the blade to be swung open by a continued pull on the operating lever 2G.

In this example, the pivoted arms I5 are shown as having rearward extensions 23 behind their pivot pins adapted to engage a stop pin M extending through opposite sides of the bracket |3 and tensioned coil springs 25 are shown as being connected, at one end, to lateral ears 2G on a depending bracket 2`| and, at the other end, to lateral fingers 28 secured to the two bifurcated arms. Incidentally, the fingers 23 are bolted to the blade arms and also serve vas clamps for flexible braided conductors 23 connected to the blade arms. The other ends of the ilexible cond-uctors are electrically connected to the bracket I3.

Such switches are subject to destructive arcing when they are manually operated and disconnected under load conditions. They are usually provided with silvered or suitably plated contact surfaces. Therefore, it is necessary that such destructive arcing shall be eliminated. To that end, there is shown an automatic arcing attachment, including an arcing plunger or conductor rod connected to be operated by the switch blade and arranged to draw the arc 'between one end of it on the contact bracket I'I instead of between the blade tip and the Contact. In this instance, the blade has a bifurcated lug 30 securely bolted to the two blade sections behind the Icontact I9 and a conductor rod 3| is pivoted to the depending lower end of the lug by a joint member 32, the connection being such that the rod may be adjusted in the joint. The other end of the rod section 3| carries a similar joint member 33 pivotally connected to an offset joint 34 to which a plunger or arcing rod 35 is adjustably secured. The arcing rod extends forwardly and at an angle through an insulating and guiding tube 36 `which is clamped in a clamping collar 31 on the depending bracket 21 and extends forwardly between the bifurcated arms of the blade. It is shown as being screw threaded into a metal socket member 38 which is bolted to the bracket II. The socket member is shown as having an elongated bore or opening 39 within which the end of the arcing rod 35 projects, so that, upon initial opening movement of the switch blade, the end of the rod will remain in contact with the socket. After the blade tip clears the jaws I9 the arc will be drawn between the inside of the socket and the end of the arcing rod. Since the arcing rod is confined within the small tube, the arc will be drawn out upon further opening movement of the switch blade and extinguished with an explosive effect. The switch blade will be opened rapidly after it is released from the jaws, due to the explosion and the action of the springs 25 until the blade extensions 23 engage the top pin 24, as shown in dotted lines in Fig. l. The arcing rod 35 will move substantially axially within the tube and its arcing end is always conned within the tube.

In actual operation, it has been found that an ordinary copper` arcing rod will last for upwards of 100 operations of the switch before its tip is burned off too far to operate successfully. When this happens, the arcing rod and its insulating tube can be replaced at a relatively small cost, which is a fraction of the cost of a new pair of jaws and/or blade. In fact, a single arcing attachment of this type will last for a period of about ve years under normal operating conditions.

From the foregoing description, it will be seen that the improved arcing attachment makes it possible to operate load-disconnecting switches without damage to contacts. Also, it enables such switches to be installed at a fraction of the cost of mechanically operated gang switches where space is not available.

Obviously, the present invention is not restricted to the particular embodiment thereof herein shown and described. Moreover, it is not indispensable that all the features of the invention be used conjointly, since they may be employed advantageously in various combinations and sub-combinations.

What is claimed is:

1. In a high tension, stick-operated switch hav ing a pivoted blade and spring biased locking jaws, a bracket carrying said jaws; a combination operating and prying lever on the blade tip; a conductor rod adjustably and pivotally connected to the blade near the tip and projecting rearwardly; a renewable arcing plunger pivotally and adjustably connected to said conductor rod and projecting forwardly at an acute angle thereto toward said jaw bracket; an arcing socket on the bracket having a bore to receive the end of the plunger so that the plunger will remain in contact with the socket until after the blade contact is broken; and an insulating and guiding tube for the plunger secured to the socket to cause the arc to be drawn and extinguished with an explosive eect.

2. In a high tension, stick-operated switch having a pivoted blade having a bifurcated rear end and spring biased locking jaws, a bracket carrying said jaws; a combination operating and prying lever on the blade tip; a conductor rod adjustably and pivotally connected to the blade near the tip and projecting rearwardly; a renewable arcing plunger pivotally and adjustably connected to said conductor rod and projecting forwardly between the arms of the blade at an acute angle thereto toward said jaw bracket; an arcing socket on the bracket having a bore to receive the end of the plunger so that the plunger will remain in contact with the socket until after the blade contact is broken; an insulating and guiding tube for the plunger screw removably secured to said socket within which the arc is extinguished; and a clamping bracket for the rear end portion of said tube mounted on the blade support.

TOMLINSON F. JOHNSON. 

